


Bust, Bust, and Away!

by magpieinthesky



Category: Phineas and Ferb, Supergirl (TV 2015)
Genre: Crossover, Gen, Misses Clause Challenge
Language: English
Status: Completed
Published: 2015-12-20
Updated: 2015-12-20
Packaged: 2018-05-07 22:03:41
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,821
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5472272
Author URL: https://archiveofourown.org/users/magpieinthesky/pseuds/magpieinthesky
Summary: <blockquote class="userstuff">
              <p>When one of Doofenshmirtz's Inators goes awry, Kara has her hands full thanks to a super-powered teenager with one single-minded purpose: bust her brothers.</p>
            </blockquote>





	Bust, Bust, and Away!

**Author's Note:**

  * For [htbthomas](https://archiveofourown.org/users/htbthomas/gifts).



> Post-Supergirl episode "Hostile Takeover," and since Supergirl didn't debut until after the summer, Phineas and Ferb are enjoying the winter following that magical, never-ending summer .

“Oh, and before you leave today Keera, I need you to--” Cat Grant stopped short in the entrance of her office, staring as her young assistant hurriedly shoved the scarf she hadn't needed on this unseasonably warm day into her oversized purse alongside a few papers. Kara froze and looked up with wide eyes, her right hand still deep inside the bag.

Cat raised one perfectly groomed eyebrow. "Going somewhere I need to know about?"

Kara snapped to attention, at once apologetic even as she shouldered the purse. "No, Ms. Grant. I put it on both of our calendars that I would leave early so I could make it down to the Science Museum. I just joined a volunteer program for young women who still want to be involved with the Fireside Girls, and I wanted to have plenty of time to get there?" Unsaid between the two of them was that Supergirl would inevitably get waylaid with an emergency, hence the recent increase in Kara's expected travel time between appointments.

By the time Kara got through her explanation, Cat had already turned away. She tossed over her shoulder, "I should have known you were a Fireside Girl. This was a minion-level task anyway, I'll get someone to get an intern to take care of it. But I expect anything newsworthy to come to me, first and exclusive."

Kara took this as her cue to hustle toward the elevators. "Of course, Ms. Grant! As always." Right after she pushed the down button, a cry for help rang in her ears. So much for that, then. Kara pushed the up button.

* * *

At the drop-off area in front of the National City Museum of Science, several children piled out of a red station wagon. Linda Flynn-Fletcher leaned across her husband to call out of the passenger seat window. "Okay, Candace, you're sure your phone is fully charged? We'll be right in as soon as we can find a place to park around here, and then you can join Stacy and the Fireside Girls. I had no idea it would be so packed on a weekday!"

Candace tapped her foot impatiently and checked behind her to see her brothers and his friends Buford and Baljeet running up the stairs to the entrance. "Yeah, of course it's charged, please Mom. Just hurry back here in time for whatever the boys end up doing today so you can bust them, I mean take a picture of them enjoying the wonders of science." Candace muttered to herself, "I only ask that there is no time machine in this museum..."

Linda gave her a look, humoring her. "Okay honey, see you soon. See you inside, boys! Stay close to your sister!" The red car drove off in search of street parking, and Candace turned back and took off running after her siblings, a grin pasted on her face.

"Did you hear that, Phineas and Ferb!?" She shouted gleefully. "I'm in charge!"

Inside the museum, Phineas and Ferb waited in the atrium, sitting under a petrified tree. The security guards patiently watched Buford and Baljeet empty their pockets of sandwiches and scientific equipment, respectively.

"Well, Ferb, what do you think we should do with all of these museum maps? There are so many possible ways for us to discover and learn about the distant past." Ferb pointed at a map and gestured, and Phineas smiled. "You're right! We've been there, so maybe start with some of the more recent scientific discoveries."

Buford sauntered up to the tree with Baljeet trailing behind. "You wouldn't believe what this nerd was able to fit into his pockets."

"Hey! You never know what you might need!" Baljeet piped up. "And you're one to talk. You have more snacks in your pockets than Mary Poppins has in her purse. Or," he quailed at Buford's snicker, "than a video game character has in his inventory?"

Phineas brightened. "Ferb, I know what we're gonna do today!"

Buford, in the process of putting a half-eaten cookie back into his pocket, held it up for the others to see. "Hey, look! I bit it in the shape of a platypus. How about that? Hey! Where’s Perry?"

”Um, back in the hotel where we left him?” Baljeet reminded him.

Buford looked at the cookie thoughtfully. "Maybe it’s still a valid question if you ask where he is existentially..."

* * *

_~doobeedoobeedooWAH~ Perry!_

At the pet-friendly National City hotel where the Flynn-Fletchers had checked in the night before, Perry lay curled up unassumingly as the housekeeping staff finished making the beds. Just as the door closed, Perry leapt to attention, put his fedora on, and hopped on top of the hotel sink. He grabbed the hairdryer attached to the wall, turned it on high, and pointed it at the mirror. The center of the mirror melted, leaving a hole big enough for Perry to jump through, leading to a series of air-pressurized tubes that pushed him to his destination: the OWCA briefing room designated by the DEO.

Awaiting him were the two DEO agents he had been briefed on earlier, Hank Henshaw and Alex Danvers. Perry saluted to them before turning to the screen featuring Major Monogram.

"Ah, hello, Agent P. Glad that you could make this special assignment happen. We wouldn't normally call the DEO in on what should be purely an OWCA matter, but I figured, what the heck. We're in Supergirl's city, anything can happen, so let's cover our bases, am I right?"

Henshaw crossed his arms and raised an eyebrow. Major Monogram coughed.

"Anyway, Agent P, Dr. Doofenshmirtz is at it again, and away from his own turf. Our sources say he's been walking around National City very slowly and picking up small rocks, and then muttering to himself. We know he's got to be up to something, it's probably evil, and we can't take the chance that Supergirl won't be involved."

Agent Danvers added, "Dr. Doofenshmirtz has been spotted at an unpopular coworking space called Werk Bench. He's picked very wisely since the people who frequent it are not very friendly and are unlikely to help if you get into an altercation."

Henshaw unfolded his arms. "We know that you prefer to work alone, but if you find yourself facing anything of an extraterrestrial nature, we strongly recommend you come back here for backup immediately. While OWCA has had some experience in this area, the DEO has far greater resources to handle such a problem."

Major Monogram cut in, clearly unused to others adding to his instructions. "Thank you, Agents Henshaw and Danvers. So there's your assignment, Agent P. Now get to it and stop him."

Perry gave all three a thumbs-up, pulled out his jetpack, and started to exit with speed. He then stopped short, landed in front of the DEO agents. He gestured forward, backward, then shrugged.

Alex, biting back a smile, pointed and said, "The exit's that way." Perry saluted in farewell and powered up the jetpack in the correct direction.

* * *

Kara made her way through security, pushing her hair back up in a ponytail and nudging her glasses further onto her nose as she picked up her purse at the other end with a quiet "thank you" to the security guard. She looked around for the recognizable Fireside Girl uniform in the crowded atrium, and was relieved to see that a cluster of girls wearing the uniforms was starting to gather under the petrified tree.

Kara extended her hearing in that direction in time for a young high voice ask sweetly, "Hi Phineas! Whatcha doin'?"

The reply startled Kara. "We're gonna build a carousel of ancient animals from this museum, but engineer it so you can take your animal anywhere you want, just like in Mary Poppins!"

Tipping her head to the side and squinting with a little half smile, Kara approached the group of children. "Excuse me, I couldn't help overhearing. Aren't you a little young to be testing Clarke's Third Law with a practical application of what was pretty much presented as magic in the movie?"

The red haired, triangle-faced boy and the boy with green hair exchanged glances. The red headed boy looked back at Kara and said optimistically, "Why, yes! Yes we are."

Kara grinned fully this time. "Okay, well I'll let you get to work on that, then. Good luck!" Turning to the girls, she said, "So I think you're the troop I'm supposed to help with your Gemstone Identification Patch, right?"

While the Fireside Girls nodded, the girl who had spoken before piped up, "Yep, that's us! Thanks for taking the time to help us!"

"Of course," Kara paused, digging through her purse for the sheet of paper she'd printed out earlier, "I'm always happy to help a fellow Fireside Girl. Now let me just make sure you're all here. Um, okay. Adyson, Ginger, Gretchen, Holly, Isabella, Katie, Milly, and it says here you're with Candace and Stacy?"

The teenage girl who had been checking her phone looked up. "Oh yeah, yeah. I'm Stacy. Candace is sort of helping and is sort of also a Fireside Girl." She shrugged and rolled her eyes with a smile. "It's complicated. But Candace should be here soon. She called to say that she had to use the bathroom right after going through security and the lines were really long. But I can just tell her where we're headed?"

Kara smiled encouragingly. "Sounds good to me. There are big signs at the gemstone exhibit so it shouldn't be hard for her to catch up. Let's head up there, and I'll test you on your knowledge so far." Quickly, Kara surreptitiously took a photo of the other children who were busily assembling the start of what was already looking to be a pretty impressive motor for the proposed carousel. She sent the photo with a message to Winn: _Get to the Science Museum NOW if you have ever loved technology or joy. You won't regret it._ She looked up and gestured for the girls to follow her. "Okay, who can tell me what makes a gem precious versus semi-precious?"

* * *

_Doofenshmirtz Evil Incorporated... coworking space!_

Dr. Heinz Doofenshmirtz was hunched over a laptop in an open plan office, trying very hard to look like he was as oblivious to his surroundings as the twenty-somethings who mainly made up the population of this work space. Doof yawned loudly and cracked his knuckles, earning him glares from every direction.

"Hey! Why don't you pay attention to your own work, huh?" Doof sniffed and pulled up a new browser, typing a little too quickly to be believable.

Just then, Perry the Platypus opened the skylight above Doofenshmirtz and landed gracefully on top of his laptop's keyboard, sticking on the letter...

_~Agent P!~_

Doof leaned to the side, peering around Perry to check the screen, where pictures of cats flicked by every few seconds. "Aw, come on Perry the Platypus! I was keeping good track of my writing with this funny little website, and now you ruined-- well, okay, I was just hitting random keys to get the new kitten pictures, but can you blame me? They’re so adorable! Anyway," the laptop snapped shut, holding Perry's tail tight and drawing him backwards into a cage seemingly made out of the laptop, the table the evil scientist had been using, and the beanbag chair that had been next to Doofenshmirtz. The effect was very comfortable, if confining. "Time to tell you about my new Inator. I thought it might be more comfortable for you to travel in a soft carrier though, and wasn't I right?"

Perry chattered reluctantly.

Doof brought Perry's carrier-cage over to a corner of the coworker space, and pulled the sheet off of a large machine. "This," he pronounced with a flourish. "Is my Rock Amplification-Inator. You see, lately I’ve been stubbing my toe on all of these pesky rocks, and it is very inconvenient. So I have decided that if they’re just a little bit bigger or glowing or just more amplified, that will better alert me to their presence, and I won’t trip over them. National City is the perfect place to test this out because as you know, it is the Tiny Rock Capital of the Tri-State Area. So many rocks to test here! So I just turn on my Rock Amplification-Inator, and voila! The rocks it hits get bigger, and more noticeable, and I will no longer stress out about whether I will stub my toe today. Then I can put all of my focus on subduing and ruling the Tri-State Area!"

Perry stared at Doof, unimpressed. Then he reached to the sides of his cage made from the beanbag and tore, leaving beans to pour out of the cage. As Doof gaped in dismay, Perry leaped out of the torn cage and smacked Doof's hand away from the machine.

"Oh, no you don't! You will not thwart me this time, Perry the Platypus!" Which was true enough in that Doof did hit the button on his Inator, but not in the sense that he had any control over it, since Doof slipped on the beans still escaping the cage and hit the Inator hard, throwing it off balance and pointing it at the Science Museum as his chin fell against the button.

* * *

Candace barreled into the room containing the gemstone exhibit, huffing and puffing, and stopped short of crashing into the irradiated blue topaz display when she finally found a group of girls she recognized. "Stacy! And Ginger and Isabella and... all of you. Hi. Have you seen my brothers?" She clutched at a stitch in her side.

Isabella tilted her head. "Hi Candace! Yes, they went to go build a carousel, and we're going to help soon, but first we're earning our Gemstone Identification Patch."

”Oh,” Candace wheezed, “they are so… busted. Phew!” 

A young woman with blond hair and glasses stepped forward to shake Candace's hand. "Hi, I'm Kara. I'm volunteering to help the troop with this patch since I completed it in record time when I was their age." She smiled self-deprecatingly, which almost soothed Candace's already ruffled feathers. Almost.

"Oh yeah?" Candace challenged. "Well I'm Candace, and I earned fifty patches in a single day. So maybe one of us can beat your record."

Kara looked askance and lifted her shoulders. "Well I didn't say my record was unbroken..."

Candace looked around her at the interactive portion of the exhibit, and picked up a bright red stone. She put it in Kara's hand, jabbing her finger at it. "What do you call this one, if you're so good at figuring these out?"

Just then, a static buzzing crackled through the air, and it looked like a ray of light arced right from a nearby window into the red stone in Kara and Candace's hands. The stone emitted a strange glow, brightening until both were bathed in red light. They jumped back, both dropping the stone which clattered to the floor harmlessly, but the damage had been done. 

Candace felt an energy diffuse through her, and all of a sudden her vision and hearing sharpened. A barrage of noises pounded at her eardrums, and she was about to clap her hands over her ears when she heard, with pinpoint accuracy, the sound of hammers and quite clearly heard Phineas say, "Ferb, could you please pass me the monkey wrench?"

Candace must have swayed on the spot, because she felt strong, sturdy hands grasp her shoulders to steady her. Kara's concerned eyes filled her vision. "Candace. Candace! Are you okay?"

 _Calm down, Candace_ , she thought to herself. _Stay cool. You’ve seen the movies, you just got hit with some super powers, no big deal. This isn't life changing or anything…_

"Hehehehehhehehehehe," Candace cackled to herself. "It's super busting time!"

* * *

Kara heard Candace's mutter and gasped. She had felt some weird energy course through her, a little like when she had been struck by lightning while trying to save Livewire. But this definitely felt different, since she still could feel her powers at full force. 

Kara looked at the younger girl again, whose cackling was starting to get a little out of control, and she saw Candace's eyes starting to heat up. She quickly slapped her hand over them and quickly whispered, "Okay kiddo, I need you to calm down unless you want to accidentally burn the museum down. Think calm thoughts," she grasped for an idea. "Like cute animals?"

Candace visibly loosened up, a more natural, relaxed smile taking over. "No problem, I will calmly bust the boys. Sooo easy to do. Totally got it."

With a whoosh, a Candace-shaped blur flew faster than the eye could see, straight through the wall, leaving a cartoonish outline behind. Kara grimaced and started loosening the top buttons of her jacket and blouse. "Fireside Girls, I'm going to call a few friends for help, but I'll need yours as well. I know how resourceful you can be, so I'll trust you to meet Candace and Supergirl at the old Tri-State Airfield as soon as you can." With that, Kara rushed out the building, changing into her suit and pulling up James on her phone's speed dial as she went.

"James Olsen."

Kara smiled even as she was concentrating on finding a super-powered teenager. "Hi James!"

"Kara!" She could hear the warmth in his voice too. She willed herself not to be distracted.

"So I'd do pleasantries, but we have a situation and I need your advice because I am pretty sure something similar has happened to Clark before but-- oh, hold on." Kara spotted Candace, who had clearly met an immovable object down in the museum courtyard, and while clearly not hurt looked a little dazed. "Basically, I'll come pick you up in a minute, just head to the CatCo roof. Bye!" She waited for James's startled goodbye and approached the teenager cautiously but authoritatively.

"Hello, young lady," Kara intoned in her best ’I've been superheroing for months more than you so listen up’ voice.

It seemed to work. Candace sat straight up. "S-Supergirl! Woah!"

With a little smile, Kara nodded. "I see you have come into some powers and would like to use them for the greater good. Can I interest you in some lessons before you, er, accidentally bust something you didn't mean to?"

Candace bit her lip, clearly torn between to bust the boys right this second and the fact that she was still sitting where she had smashed into a large rock outside the museum. She scrambled to her feet. "Ready when you are!" she called out gamely.

"That's the spirit," Kara rejoined. "First lesson is going to be a little advanced so we can get out of here and somewhere safer. Remember how to triple-jump from gym class?" Candace shook her head. "How about Super Mario?" Here she got some recognition. "Great. We're going to hold hands, run, and jump three times, and on the third jump we're going to stay up. Ready?"

They jogged to the back of the courtyard to make more room, and took three running leaps. On the third leap, Candace did in fact stay up but still gripped Kara's hand for dear life.

"Oh my gosh this is SO COOL but so scary but SO COOL! Eeeeeeee!!" Candace squealed.

Kara couldn't help laughing. Flying really was the best.

Kara was a little worried that they might not be able to get Candace of the ground again, so they flew low over the CatCo rooftop and totally surprised James by scooping him up from where he was standing.

"Kara--" James's eyes widened when he realized not only was Kara carrying him while flying, there was a girl with her who seemed to be more or less flying under her own power. "Uh, Supergirl? What is going on?"

"Candace here got hit by a ray of something while touching what I think must have been Red Kryptonite, and now she has my powers but I still have mine so I guess that's a good thing, right?" Kara pushed back the little bit of panic that rose at the thought and concentrated on getting all three to the air field safely.

* * *

Back at the Museum of Science, Winn was helping Phineas, Ferb, Baljeet, and Buford complete the electrical circuits and programming of the carousel. He had arrived shortly after Kara had sent him the text and was so glad he had been taking a personal day so he could be a part of this.

Winn gazed in awe at the completed carousel. “Thanks for letting me help you kids out. This looks really cool!”

”And thank you for convincing us to contract out for the ancient animal pieces for the carousel jumpers,” Phineas replied happily. “I guess the museum might not have been happy about us using the real things, huh?”

Buford pulled a face. “Ah, who cares? Can we give it a test ride now?”

”Wait! Wait for us, Phineas!” Isabella ran up, followed closely by the Fireside Girls and Stacy. “We need your help-- we have to get to the old Tri-State Airfield as soon as possible. Can we use the carousel to get there?”

Phineas hummed, considering. “Sure, about half of these have turbo extensions on them to get you where you need to go faster and farther. You girls can take them, and we’ll use the slower ones to take a tour of the museum.”

Isabella grinned, hopping on a Triceratops and motioning the other girls to climb onto the Microraptor, Mammoth, Dunkleosteus, and Elephant Bird carousel jumpers with her, a few sharing the jumpers together. “Sounds great to me! We’ll meet you back here when we’re done.”

The boys and Winn hopped on the Pteranodon, Irritator, Giant Toothed Platypus, Megalodon, and Mastodon carousel jumpers. “Everybody ready?” Phineas called, reaching over to hit the switch at the center of the carousel. “Whoohoo!”

The carousel spun around slowly three times, with the jumpers going up and down, and when it finished the third time around, the jumpers leaped off of the carousel, going in different directions. Winn and the boys slowly turned their jumpers toward the dinosaur exhibit. The Fireside Girls headed for the exit and waited until they were outside before engaging the turbo boosters, blasting them quickly to their destination.

* * *

As they landed and Kara set James back on his own two feet, James put his hand on his chin, thinking. "Okay, well I remember the big guy losing his powers a few times when others have taken them-- with Parasite, getting struck by lightning, and yeah, maybe Red Kryptonite... though usually that seems to have a different effect on him every time he's exposed. I can’t think of a time something like this precisely has happened, but I’m also guessing he would have kept it pretty under wraps at the time too. I think we're going to just have to hope it'll wear off soon."

Candace put her hands on her hips. "I heard that!"

Kara held out her arms disarmingly. "What he means to say is, having these powers is a big responsibility, and while I'm sure you're mature enough to understand that, it does take some getting used to if it's going to be a real part of your life. So right now, maybe let's treat it as if this is something temporary and help you get through the next day or so and then re-evaluate."

Candace was cut off by the arrival of the Fireside Girls, who were riding carousel jumpers modeled after dinosaurs and ancient mammals, fish, and birds.

"Thanks for coming, girls! I think it's about time you earn your 'Help a Superhero Save the Day' patch, how about you?" The Fireside Girls cheered.

* * *

"Okay, that's Scenario 42 dealt with," James read out of the Fireside Girls manual. "How are you feeling, Candace?"

Candace grinned. "Like I just finished a training montage. I am ready to bust some delinquents!"

Kara's face fell. "Don't you just want to fly around, enjoy your new powers for a while? I can't let you rush into danger like that."

"Are you kidding me?" Candace's eyes bugged out. "This is my opportunity to show my mom once and for all what my brothers have been up to. I'm not about to stop some robberies or whatever when Mr. Olson already said I might lose these powers any minute. This is my best shot to catch them out. Peace!" Candace shot into the sky, much more gracefully than half an hour or more ago, and headed back toward the museum.

Pulling out her phone, she dialed her mom while searching for her with newly-acquired X-ray vision. She saw her mom hit the answer button while expectantly holding it away from her ear. Good choice. "Mom! Mom! Mom! Mom!" Candace bleated into the phone. "You've got to see this! Phineas and Ferb made a carousel!"

Linda sighed deeply, working to parallel park while her husband signaled to her from the curb. "Candace, we just found a spot so we'll be over at the museum any minute now and you can show me then."

"Don't worry, Mom," Candace chortled. "Even if you aren't fast enough this time, I'll make up for it. See you in a minute!" Candace made a descent around the corner from where her parents were parking, and sauntered over while quickly X-raying the inside of the museum to make sure the central controls of the carousel were there. "Perfect, they're still here!"

Candace ran to grab her mother's arm, and loosened her grasp a little sheepishly after Linda admonished her for squeezing her elbow too tightly. At the entrance of the museum, though, they stopped short when her dad called out, "Look Linda! Up in the sky! It's Supergirl!"

At that moment, pandemonium ensued. Several rays came bursting toward the museum from a nearby office, hitting many objects and causing them to grow or glow. The stones and metals that had been used as major centerpieces of the carousel core that had been left behind in the museum grew too large and heavy, and broke apart, crushing the rest of the carousel. The stones themselves fell in a circle, strangely resembling a miniature Stonehenge in the atrium. The Fireside Girls had ridden back into the city on the carousel figures, but had abandoned them when they heard the commotion. A couple of pebbles turned boulders fell on top of the figures, crushing them and obscuring them from view. 

Candace wanted to rush out to stop this all from happening, but it seemed that the time had finally come for her new powers to fade away. She lifted into the air a few inches to hold onto the feeling a bit longer before falling back onto the balls of her feet. Candace dimly thought she could hear a gravelly voice yell, "Curse you, Perry the Platypus!" but that was a definite indication that she definitely wasn't hearing things so clearly anymore.

Linda looked from Supergirl to Candace and smiled knowingly, "Now, what was it you wanted to show me? Was it Supergirl?"

"But... but... but..." Candace gaped. Not again!

"Go on," her mom urged her. "Say hi! Ask for an autograph!"

The kids crowded around the superhero, but Supergirl looked at Candace, smiled, and beckoned her over. She handed Candace a piece of red cloth.

"I made a quick stop for this-- for the next time you play superhero. I'm sure this won't be the last time for you, but in the meantime I thought you could use a memento of today."

Candace beamed. "Thanks, Supergirl."

"You're welcome. Just remember, heroes can be found in even the most ordinary situations. You might not have a cape or powers, but you can still help make the world a better place. Though maybe try to cut your brothers some slack; it might give you some peace of mind. See you around." With that, Supergirl flew into the sky, leaving the tourists from Danville a little more dazed than the residents who had gotten somewhat used to her appearances.

"Well, that was certainly an adventure," remarked Ferb.

Phineas nodded. "It sure was-- hey! Oh, there you are, Perry! How did you get out from the hotel?" Phineas picked Perry up, who chattered unintelligibly.

Linda smiled at her family and her children's friends. "So, kids, want some snacks? I hear the food court makes a mean pie."

To a chorus of answers in the affirmative, they filed back into the museum. Stacy slung an arm around Candace's shoulder. "Superhero for a day, huh? Bet the best part was a tie between the sweet, sweet possibility of busting and flying."

Candace rolled her eyes. "Wow, Stace, and I thought I kept my motivations so close to the vest. Can you read my mind?"


End file.
